| 摘要 |
PURPOSE:To suppress an evaporation of plated zinc by preheating an Al material by a specified condition, when cladding a brazing filler metal, and brazing the zinc plated Al material, in an N2 gas atmosphere. CONSTITUTION:For instance, a fin cladded with a brazing filler metal, and a zinc-plated tube are assembled temporarily, and also a radiator core 1 applied a fluoride compound flux is heated fro 20-60min at a melting temperature or below of the brazing filler metal, in the atmospheric air by a preliminary heating furnace 2. In this case, zinc plated to the tube starts a diffusion, and a desired diffused layer is formed within said time. Also, this temperature rise is executed in the atmospheric air, therefore, the dezincing quantity is reduced comparing with a conventional system. Subsequently, a preliminarily heated core 1 is fed to a brazing furnace 3 being under an N2 atmosphere, each tube and the fin are brazed, and a brazed Al core 4 is obtained.
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